In this paper, a kind of PIα controller is designed for the synchronization of fractional order hyperchaotic Chen system. The controller is designed according to the fractional order hyperchaotic Chen system. The stability of the system is proved by the improved double parameter Mittag-Leffler function estimate theorem and the extended Gronwall lemma. Furthermore, the condition of controller parameters is pointed out which makes the fractional order hyperchaotic Chen system synchronous. Numerical simulations are presented to verify the effectiveness of the method.